linux-kernel - [PATCH RFC] mpt2/mpt3sas lock reduction for scsi-mq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 3 Apr 2015 09:58:16 -0600
From:	Jens Axboe <axboe@...com>
To:	<axboe@...nel.dk>, <linux-kernel@...r.kernel.org>,
	<linux-scsi@...r.kernel.org>
CC:	<hch@....de>
Subject: [PATCH RFC] mpt2/mpt3sas lock reduction for scsi-mq

Hi,

There's some "low" hanging fruit in the lsi mpt drivers for further
lock reduction, when running in scsi-mq mode. For each IO, they have
to lock/{get,put}/unlock a scsiio_tracker structure that is associated
with the IO. In scsi-mq mode, we can ask for some payload for each
command, so we don't have to store and manage this tracker structure
separately.

In some testing on mpt2sas, this roughly cuts the locking time in half
at just 100K IOPS. Compared to scsi-mq not being enabled, the locking
time with the patchset is reduced from ~47% to just ~4%.

-- 
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/